Centrifugal governor for internal combustion engines



Sapt. 24, 1940. M. HURST GENTRIFUGA L GOVERNOR FOR INTERNAL COMBUSTION ENGINES Filed Kay 2, 193a Patented Sept; 24, 1940 UNITED STATES CENTRIFUGAL GovEaNoa FOR. INTERNAL COMBUSTION ENGINES Max Hurst, Stuttgart, Germany, assignor to Robert Bosch Gesellschaft mit beschriinkter Haftung, Stuttgart, Germany Application May 2, 1938, Serial No. 205,614 In Germany May 11, 1937 7 Claims.

The present invention relates to centrifugal governors which, driven directly or indirectly, are suitable for governing the fuel supply of injection internal combustion engines.

. Since the adjusting forces of known governors,

which are utilized to govern engine requirements, rise in square ratio. with the engine speed, there occurs with the known centrifugal governors the or again at the maximum speed. These forces must be balanced by springs, which are to be disposed within the governor, and of which the distinguishing values such as preliminary tension, or stiffness, must be so chosen that even in the lower working, speed range the admissible degree W of non-uniformity is not exceeded. Accordingly, in the known centrifugalgovernors, the greatest possible ratio between the highest and the lowest vor no load speed is substantially of the value 511.

It is, however, desirable, especially in internal 2t combustion engines, to increase the maximum speed substantially while maintaining the hitherto usual no load speeds. For the aforesaid reason, the centrifugal governors hitherto usually adopted cannot fulfil this need, even if there 39 are used as a governor loading several sets of springs, which become operative successively, and have graded preliminary tension and stifiness, or if according to another known proposal, a part of the centrifugal mass is trapped after a prede- 35; termined stroke by stops fitted to the governor shaft and, in the range of the higher speed, only the remaining part of the originally operative mass is used for governing. As a matter of fact, in both cases the masses which revolve with the 40 governor shaft are very large in the upper speed range and necessitate a correspondingly strong.

. construction of the whole governor.

By the present invention, the above recited difficulties are overcome and thus is made possi- 45 ble an increase in the value between the highest and the lowest ratios to substantially I 1071 or even to values considerably above this figure.

According to the present invention, a transmission gear, having two drives, each of different 50 ratio, which are automatically changed or shifted from one to the other with changes in speed of thedriving shaft, is interposed between a governor shaft, about which the centrifugal weights revolve, and the driving shaft of the governor. 55 At no load and lower speeds of the driving shaft, --the governor shaft is preferably connected to the driving shaft by means of a centrifugal clutch and one of the two drives (high gear) of the transmission gear, The centrifugal clutch re- '60- leases this connection when the driving shaft "reaches a speed above no load speed, whereon the driving shaft drives the governor shaft through a'free wheel clutch and the other drive (low ear) of the transmission gear.

The invention is more particularly described 5 with reference to the accompanying drawing, which illustrates one form of construction of the invention by way of example and in which:

Figure 1 is a longitudinal section. through a centrifugal governor, and

Figure 2 is a vertical middle section through a part of the governor shown in Figure 1, and on the line 2-2 thereof.

In the drawing a sleeve I5 is driven through a pair of toothed wheels II, I2 from a shaft IIl,

which drives an injection pump (not shown), whilst through a furtherpair of toothed wheels l3 and I4, a bush l6, which is rotatably mounted on the sleeve, is driven at a greater speed. The sleeve I5 is rotatably mounted on a shaft 2|] journaled in ball bearings I1 and I8 on the governor casing 9. Into the shaft are radially inserted two guide spindles 2| for two centrifugal weights 23, which are loaded by springs 22, and which engage by. means of two bell crank levers 24 with an adjusting bolt 25 which is mounted in a bore in the shaft 20 so as to be longitudinally displaceable therein. The bolt 25 carries a collar 2B, in which is mounted a sliding ring 21- which engages with one arm of a lever 29, pivotally mounted for rotation about a spindle 28. The other arm of the lever 29 is connected by a link rod 3| with a governing member 30 of the injection pump (not shown). The spindle 28 is connected to an operating lever 92, which can be rocked about a stud 33, by means of an operating member (not shown) located outside the casing 9, for the purpose of adjusting the speed required to be maintained by the governor.

A shallow cylindrical drum 34 is connected with the shaft 20, and is open towards the driving side of the governor to accommodate a free wheel clutch, which is in engagement with the sleeve I5, and which consists of two rollers 35 and a free wheel core 36,,which engages two dogs or entraining claws I9, fitted to the sleeve I5. The outer circumference of the drum 34 is engaged by a plurality of clutch members or cheeks 31 which are loaded by' springs 38. Abutments -39 for the outer ends of these springs aresupported on the inner rim of a bowl shaped-part 40, which is rigidly connected or integral with the bush I6 and which with its inwardly directed rimpart 4| extends partly over the coupling cheeks and holds them safely without the use of additional securing elements in the position shown in Figure 1. As will be seen from Figure 2, filling elements 42 are further placed between the coupling cheeks 31, said elements serving so for guiding the cheeks and being preferably cut with the latter from an annular disc.

The governor operates in the following manner:

At low speeds of the engine consistent with no load, the coupling cheeks 31 are pressed against the outer circumference of thedrum 34 by the springs 38, and the shaft 20 is thus driven by the coupling bowl 40 which is connected with the relatively rapidly rotating bush I6. Under these conditions the rollers 35 cannot come into engagement with the inner Wall of the drum 34 and the sleeve 15, which is revolving relatively slow er, consequently runs with no load. I

During this operation, the centrifugal weights, which are driven with a comparatively large transmission gear or ratio, exercise sufiicient adjusting forces, even when the driving shaft I is revolving at low speeds, to be able to govern with certainty, the no load amount of fuel delivered. If the speed is increased, then the coupling members 3'! under the influence of centrifugal force, become released from engagement with the circumference of the drum 34 and move outwardly against the action of the springs 38 to contact with the inner peripheral face of the coupling bowl 40. The shaft 20, which is now uncoupled from the bush I6, is thus driven by the relatively slowly moving sleeve l5, since the rollers 35 are pressed firmly against the inner wall of the drum 34 by the guiding cam faces of the free wheel core 36.

The transmission ratios should be so devised by means of the toothed wheels H, l2, l3 and I4 that the centrifugal weights 23 of the governor are still driven by the more slowly rotating sleeve l5 after the centrifugal clutch 31, 40 has been disconnected, at a speed which is sufficient to prevent the centrifugal weights 23 dropping back against the shaft 20. Above that speed of the driving shaft ID at which the centrifugal clutch is disconnected, i. e. above the no load speed, there begins the working speed range, within which the governor is set by means of the operating lever 32, preferably with the use of the features characterised in the application of Hurst et a1. Serial No. 39,080 filed September 3, 1935, now Patent No. 2,117,248, to any desired speed, which can be maintained automatically by the governor within the admissible degree of non-uniformity. If the drive whichis revolving at a fairly high speed, which in the illustrated construction is represented by the bush l6 and the coupling bowl 40, is not already disconnected in the range of the no load speed by means of the centrifugal clutch, but is only disconnected after a lower limit, which lies within the working speeds,- has been exceeded, then the governor member 30 can be set to any desired speeds both in the lower and in the upper working speed'range by rocking the operating lever 32.

I declare that what I claim is;

1. A centrifugal governor suitable for governing the fuel supply of injection internal combustion engines, comprising a driving shaft, a governor shaft, centrifugal masses revolving with said governor shaft, an operable connection between said centrifugal masses and the means to be controlled thereby for displacement of said means in accordance with the position of said masses relative to said shaft, a transmission gear having two drives, each of a diflerent ratio, between said shafts, and means driven by, and responsive to the speed of, said driving shaft for changing from one driving ratio to the other of said transmission gear.

2. A centrifugal governor suitable for governing the fuel supply of injection internal combustion engines, comprising a driving shaft, 2. governor shaft, centrifugal masses revolving with said governor shaft, an operable connection between said centrifugalmasses and the means to .be controlled thereby for displacement of said means in accordance with the positions of said masses relative to said shaft, a variable transmission gear having two drives, each of a different ratio, between said shafts, a centrifugal clutch for releasing said governor shaft from operative connection with said driving shaft at a predetermined speed of said driving shaft and a free wheel clutch interconnecting said transmission gear with said governor shaft on operation of said centrifugal clutch.

3. A centrifugal governor suitable for governing the fuel supply of injection internal combustion engines, comprising a driving shaft, a governor shaft, centrifugal masses revolving with said governor shaft, an operable connection between said centrifugal masses and the means to be controlled thereby for displacement of said ,means in accordance with the position of said masses relative to said shaft, a transmission gear having relatively fast and slow elements providing two drives, each of a different ratio, between said shafts, a centrifugal clutch, responsive to the speed of said driving shaft, associated with the faster element of said transmission gear, and a free wheel clutchassociated with the slower element of said transmission gear, said free wheel clutch operating only when said centrifugal clutch cuts said faster element out of said transmission gear,

, 4. A centrifugal governor as claimed in claim 3 in which the centrifugal clutch includes a hollow cylindrical part secured to said governor shaft and centrifugal clutch members adapted for engagement with the outer circumference of said cylindrical part, and said free wheel clutch includes clutch members adapted for engagement with the inner circumference of said part. I

5. A centrifugal governor as claimed in claim 3, including a sleeve on said governor shaft and connected to said free wheel clutch, and in which the relatively faster element comprises a bush member mounted on said sleeve, which sleeve is coupled with said governor shaft through said centrifugal clutch;

6. A centrifugal governor as claimed in claim 3 and wherein the centrifugal clutch comprises a bowl shaped element having an inwardly directed rim part, coupling cheeks located in the hollow space determined by said rim part, springs resisting the outward displacement of said coupling cheeks against the periphery of said bowl, and filling elements within said bowl part serving to guide said cheeks in-their radial displacement.

'7. A centrifugal governor as claimed in claim 

